思科网络技术学院教程(第三章物理层和数据链路层).ppt
第三章,Copyright?1998,Cisco Systems,Inc.,ICRC_revision_11.3,物理层和数据链路层,物理层和数据链路层标准,Physical(bits,signals,clocking),LAN,WAN,Data Link(frames),Ethernet,802.3,802.5,FDDI,802.2 LLC,X.25LinkFrameRelay,ISDNPPP,EIA-530V.35,DialonDemand,SDLC,HDLC,V.24,HSSI,G.703,EIA/TIA-232,EIA/TIA-449,局域网数据链路子层,LLC完成上半层的软件功能MAC完成下半层的硬件功能,Media Access Control（介质访问控制）,Logical Link Control（逻辑链路控制）,Network,Data Link,Physical,LLC,MAC,MAC Frame,802.3 LLC,Packet or Datagram,物理层和逻辑地址,MAC地址,MAC地址被烧进网络接口卡的ROM芯片中,24 bits,24 bits,0000.0c12.3456,制造商代码,序列号,ROM,RAM,MAC地址判定,Host Y,Host Z,Query,Response,Example 1:Destination local,Router A,Example 2:Destination not local,Host Z,Broadcast,Host ZMAC?,Host Z,Host YMAC,Host ZMAC,Host Y,Query,Broadcast,Host ZMAC?,Host Z,Response,Host YMAC,Router AMAC,Routing Table:Net forHost Z,练习:MAC地址判定,Host A,Host B,Host D,Router C,Router C,Network Y,Network X,局域网技术,Copyright?1998,Cisco Systems,Inc.,ICRC_revision_11.3,EthernetToken RingFDDI,LAN 技术概览,FDDIDual Ring,Ethernet和IEEE 802.3,Ethernet是一种共享介质的技术，它允许多台设备同时连接、交替使用同一传输介质。,Ethernet/802.3的物理层,Host,10BaseT双绞线,10Base2以太网细缆 10Base5以太网粗缆,PC,Mac,Sun,Host,Hub,MAC,Ethernet/802.3接口,Cisco路由器的Ethernet/802.3的接口名字使用字母E加一个数字(例如：E0),a56,0000.0c12.7c4d,E0,E1,0000.0c12.83e2,Ethernet/802.3工作原理,A,B,C,D,Ethernet/802.3工作原理,A,B,C,D,Ethernet/802.3工作原理,A,B,C,D,D,Ethernet/802.3工作原理,A,B,C,D,D,B and C,Ethernet/802.3 广播,D,C,B,A,Application,Presentation,Session,Transport,Network,Data Link,Physical,A,B,C,D,Ethernet/802.3 的冲突检测,Ethernet/802.3的冲突检测,C,D,Ethernet/802.3的冲突检测,C,D,Collision,Ethernet/802.3的冲突检测,Collision,A,B,C,D,C,D,Ethernet/802.3的冲突检测,A,B,C,D,Collision,A,B,C,D,JAM,JAM,JAM,JAM,JAM,JAM,Ethernet/802.3的冲突检测,A,B,C,D,Collision,A,B,C,D,JAM,JAM,JAM,JAM,JAM,JAM,广域网技术,Copyright?1998,Cisco Systems,Inc.,ICRC_revision_11.3,WAN 技术概览,SDLC,HDLCLAPBPPP,X.25Frame RelayISDN,WAN的物理层协议,(Modem),Data Terminal Equipment（与数据通信网相连的用户设备）,DTE,Data Circuit-Terminating Equipment（数据通信网末端设备）CSU信道服务单元DSU数据服务单元,DCE,EIA/TIA-232V.35X.21HSSIOthers,CSU/DSU,WAN接口电缆,Data Link Layer:WAN Protocols,SDLCSynchronous Data Link ControlHDLCHigh-Level Data Link ControlLAPBLink Access Procedure,BalancedFrame RelaySimplified version of HDLC framing PPPPoint-to-Point ProtocolX.25Packet level protocol(PLP)ISDNIntegrated Services Digital Network,
